The present invention relates to a continuously variable automotive transmission comprising a fluid torque converter and a continuously variable transmission mechanism employing a V belt.
There are several known continuously variable automotive transmissions in which engine power is transmitted through a V-belt continuously variable transmission mechanism, either through a fluid torque converter or clutches and through a speed reducer gear train for driving vehicle wheels, such as U.S. Pat. Nos. 4,548,100, 4,559,850, 4,605,112 and 4,624,153 and the two Japanese Patent Publications noted below.
Japanese Laid-Open Patent Publication No. 55-63051 discloses a continuously variable automotive transmission wherein the turbine shaft of a fluid torque converter is disposed coaxially with the driver shaft of a V-belt continuously variable transmission mechanism, and the driven shaft thereof is coupled to either a gear mechanism including two parallel gear trains for selecting forward and rearward gear positions or a forward/rearward-gear-position selecting mechanism including a clutch and planetary gear mechanism which are arranged parallel to each other.
Another continuously variable automotive transmission disclosed in Japanese Laid-Open Patent Publication No. 57-192666 includes a forward/rearward-gear-position selecting gear mechanism disposed coaxially with the turbine shaft of a fluid torque converter.
With the conventional arrangements, since the turbine shaft and the driver shaft are positioned in coaxial relation to each other and the forward/rearward-gear-position selecting mechanism (which may comprise two gear trains or a clutch and a planetary gear mechanism) is coupled to either the driven shaft or the driver shaft, the conventional continuously variable transmissions are of axially large dimensions, and contain a large number of gears. Further, the drive torque is transmitted through the V-belt continuously variable transmission mechanism not only when the automobile is moving forwardly, but also when it is moving rearwardly.